Tapering metal bodies.



G. F. JENKINS.

TAPEBING METAL BODIES.

APPLICATION nun JULYZI, 1911.

1,017,671. Patented Feb. 20, 1912,

UNITED STATES PATENT OFFICE.

CHARLES FRANCIS JENKINS, OF WASHINGTON, DISTRICT OF COLUMBIA.

TAPERING METAL BODIES.

T 0 all whom it may concern:

Be it known that I, CHARLES FRANCIS JENKINS, a citizen of the UnitedStates, residing at WVashington, Districtof Columbia, have inventedcertain new and useful Improvements in Tapering Metal Bodies, of whichthe followingis a specification, reference being had therein to theaccompanying drawing.

This invention relates to tapering or pointing small metal bodies, suchas needles or needle-like appliances, and similarlydiminishingplate-like bodies, such as cutting tools, for example, by the aid ofelectrolytic action.

In the accompanying drawings, Figure 1' shows in side, partly sectional,elevation apparatus for polnting needless Fig. 2 shows, in crosssection, analogous devices for operating upon a razor. Fi 3 shows inplan devices constituting a di erent'application of the same generalideas in stropping a razor. Fig. 4 illustrates the application of thesame ideas in grinding a chisel.

All these embodiments are based upon the fact that an electric currentcauses acidulated liquid to attack steel much more actively than whenthe current is not employed. I have found that to secure this rapidelectrolytic action it is not necessary to immerse the metal in a liquidbath,'but that wherever the acidulated liquid is present and completesthe circuit through the steel body there is, by reason of the current,

more or less increase of effect upon the steel.

In Fig. 1 A represents a glass vessel containing an electrolytic liquidB. C is a lead plate lying in the bottom of the vessel and connectedwith a conductor D leading to any suitable source, X, of current andhaving that portion passing through the liquid insulated as shown at D.E represents a conducting bar or clamp, sustained by bearings F andslowly reciprocated by a crank-plate and pitman G. The bar or clamp Eholds in vertical position in the liquid B a series H of steel needles,for example, to be tapered and pointed. A wire D leads from the,,current source X to the bar E. If now current be supplied from Xcircuit is established through D, E, H, B, C, D, and the steel needles Hare all attacked, the action being most rapid at their lower ends andprogressively decreasing as distance from the lead plate increases, withSpecification of Letters Patent.

Application filed July 27, 1911.

Patented Feb. 20, 1912.

Serial No. 640,930.

the result that the needles quickly become pointed, although they are,of course given a mat surface.

Fig. 2 shows in cross section an analogous cell A with a razor blade Htaking the place of the needles of Fig. 1. Fig. 3 illus trates embeddingin a razor strop I conducting wiresI connected with a source X ofcurrent. The strop being saturated with a suitable electrolyte, a razorJ electrically connected to the source X and stropped in the usual waywill be very rapidly af fected or brought to condition for smoothlycutting.

In Fig. 4, K represents diagrammatically a porous stone rotating withits lower side in a trough L containing acidulated li uicl. A tool M tobe ground and the sha t N which carries the stone are connected,respectively, with the positive and negative poles of a generator. \Vhenthe tool rests upon the saturated porous stone, circuit is completed andthe tool is sharpened quickly by the combined action of the two agents.

It is to be noted that when a bath is used as 'in Fig. 1, it isadvantageous to cause relative movement of thearticle acted upon and theelectrolyte and a means to this end is there illustrated. I have foundthis method when practiced as illustrated in Fig. 1 highly advantageousin tapering and pointing extremely slender broaohes, used by dentists,and the like tools and articles.

What I claim is: 1. For sharpening cutting implements, the combinationwith a porous sharpening material containing an electrolyte, of meansfor supplying an electric current through said electrolyte and theimplement to be sharpened when the-latter is placed upon the abradingmaterial.

2. The combination with a porous strop saturated. with an electrolyteand having electrical conductors embedded therein, of a source ofelectric current, means for con-

